STA60104 QUANTITATIVE METHODS FOR BUSINESS
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GROUP ASSIGNMENT
AUGUST 2022 SEMESTER
QUANTITATIVE METHODS FOR BUSINESS
STA60104
Question 1 (15 marks)
An experiment to make artificial rain is performed using silver iodide to increase rainfall. The data shown in Table 1 compares the amount of rain (in acre-feet) produced before and after the use of silver iodide for seeding individual clouds.
No. |
Before the use of silver iodide |
After the use of silver iodide |
1 |
1 |
4.1 |
2 |
4.9 |
7.7 |
3 |
4.9 |
17.5 |
4 |
11.5 |
31.4 |
5 |
17.3 |
32.7 |
6 |
21.7 |
40.6 |
7 |
24.4 |
92.4 |
8 |
26.1 |
115.3 |
9 |
26.3 |
118.3 |
10 |
28.6 |
119 |
11 |
29 |
129.6 |
12 |
36.6 |
198.6 |
13 |
41.1 |
200.7 |
14 |
47.3 |
242.5 |
15 |
68.5 |
255 |
16 |
81.2 |
274.7 |
17 |
87 |
274.7 |
18 |
95 |
302.8 |
19 |
147.8 |
334.1 |
20 |
163 |
430 |
21 |
244.3 |
489.1 |
22 |
321.2 |
703.4 |
23 |
345.5 |
978 |
24 |
372.4 |
1656 |
25 |
830.1 |
1697.8 |
26 |
1202.6 |
2745.6 |
Table 1: Rain volume (in acre-feet) produced before and after the use of silver iodide.
Before answering the questions, watch the following videos for the guidelines to construct
box and whisker plot:
(i) https://www.youtube.com/watch?v=39lsUsJsc2c
(ii) https://www.youtube.com/watch?v=mhaGAaL6Abw
(a) |
Identify the first quartile (Q1), median (Q2), and the third quartile (Q3) for rain volume before and after the use of silver iodide for seeding individual clouds. Use the function QUARTILE.EXC in Excel to find the quartiles. (3 marks) |
(b) Using information from part (a), compute the lower outlier limit and the upper outlier
limit for rain volume before and after the use of silver iodide for seeding individual clouds. What are the values of the lower and upper whiskers of the box and whisker plots for rain volume before and after the use of silver iodide for cloud seeding? (5 marks)
(c) Identify the outliers in Table 1. Would the mean be a good summary statistic for central tendency in this case? Explain your answer. (3 marks)
(d) Using information from parts (a) to (c), sketch the box and whisker plots for this data set using Excel. Compare the two box and whisker plots that you produced for rain volume before and after the use of silver iodide for seeding individual clouds. What do the plots suggest about the effectiveness of the use of silver iodide for cloud seeding? (4 marks)
Question 2 (10 marks)
We will discuss this question during the lecture.
Let the random variable X follows the binomial distribution with parameters n and p = 0.7.
(a) By using the Data Analysis Tool in Excel, generate 100 random numbers from the
above binomial distribution, with n as follows
(i) |
n = 5 |
(ii) |
n = 20 |
(iii) |
n = 50 |
(iv) |
n = 100 |
Show the random numbers generated in Excel, and attach the Excel output in the appendix of your assignment. (2 marks)
To generate random number, you need to install the Data Analysis ToolPak in Microsoft Excel, watch the following video on how to install the Data Analysis ToolPak in Microsoft Excel:
https://www.youtube.com/watch?v=_yNxLFagKgw
(b) For each (a)(i) to (a)(iv),
(i) plot a histogram of the 100 random numbers generated using Excel, and (2 marks)
(ii) comment on the shape of the distribution as n increases. (1 mark)
(c) The random numbers generated in part (a) represent the number of successes from random samples of size n from the binomial distribution. For (a)(i) and (a)(iv),
(i) determine the proportion of samples with more than 80% successes, i.e. where X 0.8n , for (a)(i) and (a)(iv). For example, for (a)(i), determine the proportion of samples with X 4 , and for (a)(iv), determine the proportion of samples where X 80 . (1 mark)
(ii) compare the proportion of samples obtained in part (c)(i) with the probability
that would have been obtained if Xis normally distributed with mean = np
and variance 2 = npq . Comment on what is observed, and make a conclusion. (4 marks)
Question 3 (10 marks)
Based on the data given in the Excel file, select any two countries (one high-income country and one low-income country). Let the population size be the dependent variable (y), and the year (1960 – 2021) be the independent variable (x), answer the following questions:
(a) |
Construct the scatter plots (with straight lines) of the two countries on two separate graphs from Excel. Comment on the significant features from the graphs (identify any unusual points, if any, and observe the trend line). Compare the results of the population size in these two countries. (4 marks) |
(b) |
Determine the correlation between the population and year, and develop the estimated equation for the low-income country that you have chosen earlier. Obtain the summary output from Excel and interpret the coefficient for the independent variable. Determine whether the regression model is significant at 1% significance level. Write a short report on your analysis. (6 marks) |
To run regression analysis, you need to install the Data Analysis ToolPak in Microsoft Excel, watch the following video on how to install the Data Analysis ToolPak in Microsoft Excel:
https://www.youtube.com/watch?v=_yNxLFagKgw
Watch the following video on how to obtain the regression output using Data Analysis Tool in Excel:
https://www.youtube.com/watch?v=B-tFvua7qV4
2022-10-24